.TH std::slice_array::operator= 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::slice_array::operator= \- std::slice_array::operator=

.SH Synopsis
   void operator=( const T& value ) const;                             \fB(1)\fP
   void operator=( const std::valarray<T>& val_arr ) const;            \fB(2)\fP
   const slice_array& operator=( const slice_array& other_arr ) const; \fB(3)\fP

   Assigns values to all referred elements.

   1) Assigns value to all of the elements.
   2) Assigns the elements of val_arr to the referred to elements of *this.
   3) Assigns the selected elements from other_arr to the referred to elements of
   *this.

.SH Parameters

   value     - a value to assign to all of the referred elements
   val_arr   - std::valarray to assign
   other_arr - std::slice_array to assign

.SH Return value

   1,2) \fI(none)\fP
   3) *this

.SH Example


// Run this code

 #include <iostream>
 #include <valarray>

 void print(char const* remark, std::valarray<int> const& v = {})
 {
     std::cout << remark;
     if (v.size() != 0)
     {
         std::cout << ':';
         for (int e : v)
             std::cout << ' ' << e;
     }
     std::cout << '\\n';
 }

 int main()
 {
     std::valarray<int> v1{1, 2, 3, 4, 5, 6, 7, 8};
     std::slice_array<int> s1 = v1[std::slice(1, 4, 2)];
     print("v1", v1);
     print("s1", s1);

     print("\\n(1) operator=( const T& )");
     print("s1 = 42");
     s1 = 42; // (1)
     print("s1", s1);
     print("v1", v1);

     print("\\n(2) operator=( const std::valarray<T>& )");
     std::valarray<int> v2{10, 11, 12, 13, 14, 15};
     print("v2", v2);
     print("s1 = v2");
     s1 = v2; // (2)
     print("s1", s1);
     print("v1", v1);

     print("\\n(3) operator=( const slice_array& )");
     v1 = {1, 2, 3, 4, 5, 6, 7, 8};
     std::slice_array<int> s2 = v1[std::slice(0, 4, 1)];
     std::slice_array<int> s3 = v2[std::slice(1, 4, 1)];
     print("v1", v1);
     print("v2", v2);
     print("s2", s2);
     print("s3", s3);
     print("s2 = s3");
     s2 = s3; // (3) Note: LHS and RHS must have same size.
     print("s2", s2);
     print("v1", v1);
 }

.SH Output:

 v1: 1 2 3 4 5 6 7 8
 s1: 2 4 6 8

 \fB(1)\fP operator=( const T& )
 s1 = 42
 s1: 42 42 42 42
 v1: 1 42 3 42 5 42 7 42

 \fB(2)\fP operator=( const std::valarray<T>& )
 v2: 10 11 12 13 14 15
 s1 = v2
 s1: 10 11 12 13
 v1: 1 10 3 11 5 12 7 13

 \fB(3)\fP operator=( const slice_array& )
 v1: 1 2 3 4 5 6 7 8
 v2: 10 11 12 13 14 15
 s2: 1 2 3 4
 s3: 11 12 13 14
 s2 = s3
 s2: 11 12 13 14
 v1: 11 12 13 14 5 6 7 8

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

     DR    Applied to           Behavior as published            Correct behavior
   LWG 123 C++98      overload \fB(2)\fP was non-const                 made const
   LWG 253 C++98      the copy assignment operator was private   made public
   LWG 621 C++98      the copy assignment operator was non-const made const
